Spinal infection and abscess: Clinical sciences

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Introduction0:00–0:52

A spinal infection and abscess occurs from an inoculation of bacteria, fungus, or parasites in the vertebrae, intervertebral disc, or adjacent paraspinal tissues.
Spinal infections can progress into an epidural abscess, a walled-off collection of pus in the epidural space, which can compress and damage the spinal cord.
If the infection is within the disc space, spondylodiscitis can occur, while infection of the vertebral bone itself is referred to as vertebral osteomyelitis.
Although these infections are rare, they're serious conditions that can lead to severe complications, such as paralysis or death, so timely diagnosis and appropriate treatments are very important.Alright, when a patient presents with chief concern suggestive of spinal infection or abscess, your first step is to perform an ABCDE assessment to determine if the patient is unstable or stable.

Unstable Patient0:52–3:40

If the patient is unstable, stabilize the airway, breathing, and circulation. Next, obtain IV access and initiate IV fluids for resuscitation.
Then, continuously monitor vital signs including pulse oximetry, blood pressure, and heart rate. Once acute management has been initiated, your next step is to obtain a focused history and physical exam, in addition to labs including a CBC, CRP, ESR, and two sets of blood cultures.
On history, your patient might report fevers, back pain, shooting nerve pain down the extremities, motor weakness, sensory changes, or bowel and bladder dysfunction.
Additionally, history might reveal risk factors, such as diabetes, intravenous drug use, a chronic indwelling venous catheter, a concurrent infection elsewhere in the body such as tuberculosis, a recent spinal procedure, or immunocompromised state.
Physical exam will reveal hypotension and tachycardia, both concerning signs of sepsis. On palpation, you’ll also notice spinal tenderness; and sometimes a focal area of fluctuance; as well as neurological deficits like motor weakness, radiculopathy, or sometimes even paralysis.
On labs, you can expect to find leukocytosis with elevated CRP and ESR. With this presentation, you should suspect a spinal epidural infection or abscess with sepsis.
To confirm your diagnosis, obtain an MRI of the spine with contrast. Keep in mind, the patient must be stabilized first prior to getting the MRI.
Now, once you obtain the MRI, you might see a fluid collection with rim enhancement and a hypointense center, dural enhancement, paraspinal and bone marrow edema, and longitudinal extension along the spinal column, which are all consistent with a spinal epidural infection or abscess, in this case with sepsis.
For treatment, start IV empiric antibiotics; and check the blood cultures to identify the causative pathogen and possibly tailor antibiotic coverage accordingly.
Next, consult the surgical team right away for decompression and drainage. If drainage is performed, make sure to send a sample of the fluid for cultures and sensitivities.
Alright, let's go back and talk about stable patients. Your first step is to obtain a focused history and physical, in addition to labs including CBC, CRP, ESR, and two sets of blood cultures.

Stable Patients3:40–5:06

Patients will again typically report a history of fevers, back pain, shooting nerve pain in the extremities, motor weakness, sensory changes, or bowel and bladder dysfunction.
Similarly, patients might have risk factors like diabetes, intravenous drug use, a chronic indwelling venous catheter, concurrent infection, recent spinal procedure or trauma, or an immunocompromised state.
Physical exam often reveals spinal tenderness, and sometimes a focal area of fluctuance; as well as neurological deficits such as motor weakness, radiculopathy, bowel and bladder dysfunction, or even paralysis.
Labs can be normal or show leukocytosis with elevated CRP and ESR. With these findings, you should suspect a spinal infection or abscess.
The modality of choice to further evaluate is an MRI of the spine with contrast. MRIs provide anatomic visualization of the parts of the spine affected by the infection that can help with your diagnosis.

Spinal Epidural Abscess5:06–5:58

So in that case, let’s look at some MRI findings. If you see a fluid collection with rim enhancement and a hypointense center, dural enhancement, paraspinal and bone marrow edema, along with longitudinal extension along the spinal column, you can diagnose your patient with a spinal epidural abscess.
In terms of management, start the patient on IV empiric antibiotics; and check the blood cultures to identify the causative pathogen and possibly tailor antibiotic coverage.
Then, consult the surgical team for decompression and drainage. The purulent drainage should be sent for cultures and sensitivities.
Of note, most patients need long term IV antibiotics therapy for a total of 4 to 6 weeks.Now, let’s go back and discuss another set of MRI findings.

Spondylodiscitis5:58–7:50

MRI typically reveals destruction and enhancement of the intervertebral discs, with associated edema and destruction of the adjacent vertebral bodies.
If you see this, you can diagnose your patient with spondylodiscitis.Here’s a clinical pearl! Spondylodiscitis often occurs from hematogenous spread or adjacent soft tissue infection, and the most common causative pathogen is Staphylococcus aureus.
The most common original source is genitourinary, and the most commonly affected site is the lumbar spine, which makes up more than half of the cases!
Okay, let’s talk about treatment. Start the patient on IV empiric antibiotics; and check the blood cultures to identify the causative pathogen and possibly tailor antibiotics accordingly.
Of note, patients will need IV antibiotics for 2 to 4 weeks, and then they can switch to PO antibiotics for another prolonged course of 6 to 12 weeks.
The total duration of antibiotic therapy depends on the clinical progression of the patient. Additionally, patients should use orthosis for 6 weeks.
Bed rest is only recommended if there’s ongoing spinal instability. Otherwise, aggressive physiotherapy is recommended.
If there’s no improvement after this time period or neurologic deficits arise or persist, then consult the surgical team for debridement.Here’s a clinical pearl!
Keep in mind that some patients can have negative cultures, in which case you can treat them with a full course of empiric antibiotics.
If blood cultures are negative, the next best step in management is percutaneous biopsy. Alright, let’s go over our final set of MRI findings!

Vertebral Osteomyelitis7:50–9:03

You might see vertebral body bone marrow signal abnormality, loss of intervertebral disc space height, loss of margins between the vertebral body and disc space, with vertebral body end plate destruction, and surrounding bone marrow and soft tissue edema.
If these are your findings, suspect vertebral osteomyelitis. To confirm your diagnosis, you can obtain an image-guided biopsy and culture.
You can expect the biopsy to show bony and soft tissue necrosis, granulocyte inflammatory infiltrate and microorganisms.
Additionally, tissue cultures will often show aerobic, fungal, or mycobacterial growth. Both biopsy and culture results confirm your diagnosis of vertebral osteomyelitis.
Let’s end with management. As with other spinal infections, start the patient on IV empiric antibiotics; and check the blood cultures to identify the causative pathogen and possibly tailor antibiotics accordingly.
Lastly, consult the surgical team for debridement and spine stabilization.Alright, as a quick recap… Spinal infection and abscess occurs from seeding of bacteria, fungus or parasites in the vertebrae, epidural space, IV discs or surrounding soft tissue.

Review9:03–10:17

For unstable patients with neurological deficits and sepsis, first stabilize the patient, then obtain an MRI of the spine.
If the MRI shows spinal epidural abscess, start IV empiric antibiotics followed by surgical decompression and drainage. On the other hand, for stable patients, the first step is to obtain the MRI to confirm your diagnosis.
Spinal epidural abscesses are treated with IV empiric antibiotics and surgical decompression and drainage. Spondylodiscitis is typically treated with IV then oral antibiotics and non-surgical management like bedrest and orthosis.
Lastly, vertebral osteomyelitis needs a biopsy and tissue culture for confirmation; and can be treated with IV empiric antibiotics as well as surgical debridement and spine stabilization.